Optical coherence tomography (OCT) has been widely and successfully used in the imaging of biological tissues (Huang, D., E. A. Swanson, et al. (1991). “Optical coherence tomography.” Science 254 (5035): 1178-81; and U.S. Pat. Nos. 5,321,501 and 5,459,570). A large of number of applications have been found for this technology as evidenced by a number of review articles [Swanson E. A. et al. “Optical coherence tomography, Principles, instrumentation, and biological applications” in Biomedical Optical Instrumentation and Laser-Assisted Biotechnology, A. M. Verga Scheggi et al. (eds.) pages: 291-303, 1996 Kluwer Academic Publishers, Printed in the Netherlands; Schmitt, J. M. “Optical coherence tomography (OCT): a review” IEEE Journal of Selected Topics in Quantum Electronics 5(4):1205-1215 (1999); Fujimoto, J. G. et al. “Optical Coherence Tomography: An Emerging Technology for Biomedical Imaging and Optical Biopsy” Neoplasia 2:9-25 (2000); Rollins A. M. et al. “Emerging Clinical Applications of Optical Coherence Tomography” Optics and Photonics News 13(4): 36-41 (2002); Fujimoto, J. G. “Optical coherence tomography for ultrahigh resolution in vivo imaging.” Nature Biotechnology 21(11): 1361-7 (2003)].
Descriptions of the modern use of OCT in ophthalmology are given by Wojtkowski, et al., [Ophthalmology 112(10):1734 (2005)] and by Lee et al. [Optics Express 14(10):4403 (2006).]
The publications and patents cited above as well as those cited throughout this patent application are incorporated herein by reference.
To make a clinically useful device, in ophthalmology, typically OCT is used in conjunction with a fundus viewer, [User Manual for the Zeiss OCT Model 3000 pp. 3-1 to 3-4 and p. 9-1, U.S. No. Pat. 5,506,634] or with a scanning laser ophthalmoscope (SLO) [U.S. Pat. Nos. 6,769,769 and 7,382,464]. These secondary devices provide a live view of the retina, this live view being en-face (from the front) as opposed to tomographic (in cross-section), for use in correctly placing the OCT scan so the tomograms are acquired at the locations of interest. As technology has advanced, OCT systems are now fast enough to collect axial scans over a two-dimensional transverse extent of the retina, resulting in three dimensional data volumes, which are acquired within the time a patient can comfortably keep his eye open and steady. These volume scans can be processed to give a useful high-contrast en-face view [U.S. Pat. No. 7,301,644]. This process would enable a live en-face view from the OCT scanner alone, without the secondary fundus viewing system, if the rate of en-face views were fast enough.
Thus there would be utility, in at least the field of ophthalmology, for an OCT scanner that can be quickly re-configured to trade speed for axial resolution, allowing a mode of operation sufficiently fast to practically replace the fundus viewer with an en-face image derived from an OCT volume.